diff options
Diffstat (limited to 'net/sunrpc/xprtrdma/svc_rdma_rw.c')
| -rw-r--r-- | net/sunrpc/xprtrdma/svc_rdma_rw.c | 1165 |
1 files changed, 1165 insertions, 0 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c new file mode 100644 index 000000000..11cf7c646 --- /dev/null +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c @@ -0,0 +1,1165 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2016-2018 Oracle. All rights reserved. + * + * Use the core R/W API to move RPC-over-RDMA Read and Write chunks. + */ + +#include <rdma/rw.h> + +#include <linux/sunrpc/xdr.h> +#include <linux/sunrpc/rpc_rdma.h> +#include <linux/sunrpc/svc_rdma.h> + +#include "xprt_rdma.h" +#include <trace/events/rpcrdma.h> + +static void svc_rdma_write_done(struct ib_cq *cq, struct ib_wc *wc); +static void svc_rdma_wc_read_done(struct ib_cq *cq, struct ib_wc *wc); + +/* Each R/W context contains state for one chain of RDMA Read or + * Write Work Requests. + * + * Each WR chain handles a single contiguous server-side buffer, + * because scatterlist entries after the first have to start on + * page alignment. xdr_buf iovecs cannot guarantee alignment. + * + * Each WR chain handles only one R_key. Each RPC-over-RDMA segment + * from a client may contain a unique R_key, so each WR chain moves + * up to one segment at a time. + * + * The scatterlist makes this data structure over 4KB in size. To + * make it less likely to fail, and to handle the allocation for + * smaller I/O requests without disabling bottom-halves, these + * contexts are created on demand, but cached and reused until the + * controlling svcxprt_rdma is destroyed. + */ +struct svc_rdma_rw_ctxt { + struct llist_node rw_node; + struct list_head rw_list; + struct rdma_rw_ctx rw_ctx; + unsigned int rw_nents; + struct sg_table rw_sg_table; + struct scatterlist rw_first_sgl[]; +}; + +static inline struct svc_rdma_rw_ctxt * +svc_rdma_next_ctxt(struct list_head *list) +{ + return list_first_entry_or_null(list, struct svc_rdma_rw_ctxt, + rw_list); +} + +static struct svc_rdma_rw_ctxt * +svc_rdma_get_rw_ctxt(struct svcxprt_rdma *rdma, unsigned int sges) +{ + struct svc_rdma_rw_ctxt *ctxt; + struct llist_node *node; + + spin_lock(&rdma->sc_rw_ctxt_lock); + node = llist_del_first(&rdma->sc_rw_ctxts); + spin_unlock(&rdma->sc_rw_ctxt_lock); + if (node) { + ctxt = llist_entry(node, struct svc_rdma_rw_ctxt, rw_node); + } else { + ctxt = kmalloc(struct_size(ctxt, rw_first_sgl, SG_CHUNK_SIZE), + GFP_KERNEL); + if (!ctxt) + goto out_noctx; + + INIT_LIST_HEAD(&ctxt->rw_list); + } + + ctxt->rw_sg_table.sgl = ctxt->rw_first_sgl; + if (sg_alloc_table_chained(&ctxt->rw_sg_table, sges, + ctxt->rw_sg_table.sgl, + SG_CHUNK_SIZE)) + goto out_free; + return ctxt; + +out_free: + kfree(ctxt); +out_noctx: + trace_svcrdma_no_rwctx_err(rdma, sges); + return NULL; +} + +static void __svc_rdma_put_rw_ctxt(struct svcxprt_rdma *rdma, + struct svc_rdma_rw_ctxt *ctxt, + struct llist_head *list) +{ + sg_free_table_chained(&ctxt->rw_sg_table, SG_CHUNK_SIZE); + llist_add(&ctxt->rw_node, list); +} + +static void svc_rdma_put_rw_ctxt(struct svcxprt_rdma *rdma, + struct svc_rdma_rw_ctxt *ctxt) +{ + __svc_rdma_put_rw_ctxt(rdma, ctxt, &rdma->sc_rw_ctxts); +} + +/** + * svc_rdma_destroy_rw_ctxts - Free accumulated R/W contexts + * @rdma: transport about to be destroyed + * + */ +void svc_rdma_destroy_rw_ctxts(struct svcxprt_rdma *rdma) +{ + struct svc_rdma_rw_ctxt *ctxt; + struct llist_node *node; + + while ((node = llist_del_first(&rdma->sc_rw_ctxts)) != NULL) { + ctxt = llist_entry(node, struct svc_rdma_rw_ctxt, rw_node); + kfree(ctxt); + } +} + +/** + * svc_rdma_rw_ctx_init - Prepare a R/W context for I/O + * @rdma: controlling transport instance + * @ctxt: R/W context to prepare + * @offset: RDMA offset + * @handle: RDMA tag/handle + * @direction: I/O direction + * + * Returns on success, the number of WQEs that will be needed + * on the workqueue, or a negative errno. + */ +static int svc_rdma_rw_ctx_init(struct svcxprt_rdma *rdma, + struct svc_rdma_rw_ctxt *ctxt, + u64 offset, u32 handle, + enum dma_data_direction direction) +{ + int ret; + + ret = rdma_rw_ctx_init(&ctxt->rw_ctx, rdma->sc_qp, rdma->sc_port_num, + ctxt->rw_sg_table.sgl, ctxt->rw_nents, + 0, offset, handle, direction); + if (unlikely(ret < 0)) { + svc_rdma_put_rw_ctxt(rdma, ctxt); + trace_svcrdma_dma_map_rw_err(rdma, ctxt->rw_nents, ret); + } + return ret; +} + +/* A chunk context tracks all I/O for moving one Read or Write + * chunk. This is a set of rdma_rw's that handle data movement + * for all segments of one chunk. + * + * These are small, acquired with a single allocator call, and + * no more than one is needed per chunk. They are allocated on + * demand, and not cached. + */ +struct svc_rdma_chunk_ctxt { + struct rpc_rdma_cid cc_cid; + struct ib_cqe cc_cqe; + struct svcxprt_rdma *cc_rdma; + struct list_head cc_rwctxts; + ktime_t cc_posttime; + int cc_sqecount; + enum ib_wc_status cc_status; + struct completion cc_done; +}; + +static void svc_rdma_cc_cid_init(struct svcxprt_rdma *rdma, + struct rpc_rdma_cid *cid) +{ + cid->ci_queue_id = rdma->sc_sq_cq->res.id; + cid->ci_completion_id = atomic_inc_return(&rdma->sc_completion_ids); +} + +static void svc_rdma_cc_init(struct svcxprt_rdma *rdma, + struct svc_rdma_chunk_ctxt *cc) +{ + svc_rdma_cc_cid_init(rdma, &cc->cc_cid); + cc->cc_rdma = rdma; + + INIT_LIST_HEAD(&cc->cc_rwctxts); + cc->cc_sqecount = 0; +} + +/* + * The consumed rw_ctx's are cleaned and placed on a local llist so + * that only one atomic llist operation is needed to put them all + * back on the free list. + */ +static void svc_rdma_cc_release(struct svc_rdma_chunk_ctxt *cc, + enum dma_data_direction dir) +{ + struct svcxprt_rdma *rdma = cc->cc_rdma; + struct llist_node *first, *last; + struct svc_rdma_rw_ctxt *ctxt; + LLIST_HEAD(free); + + first = last = NULL; + while ((ctxt = svc_rdma_next_ctxt(&cc->cc_rwctxts)) != NULL) { + list_del(&ctxt->rw_list); + + rdma_rw_ctx_destroy(&ctxt->rw_ctx, rdma->sc_qp, + rdma->sc_port_num, ctxt->rw_sg_table.sgl, + ctxt->rw_nents, dir); + __svc_rdma_put_rw_ctxt(rdma, ctxt, &free); + + ctxt->rw_node.next = first; + first = &ctxt->rw_node; + if (!last) + last = first; + } + if (first) + llist_add_batch(first, last, &rdma->sc_rw_ctxts); +} + +/* State for sending a Write or Reply chunk. + * - Tracks progress of writing one chunk over all its segments + * - Stores arguments for the SGL constructor functions + */ +struct svc_rdma_write_info { + const struct svc_rdma_chunk *wi_chunk; + + /* write state of this chunk */ + unsigned int wi_seg_off; + unsigned int wi_seg_no; + + /* SGL constructor arguments */ + const struct xdr_buf *wi_xdr; + unsigned char *wi_base; + unsigned int wi_next_off; + + struct svc_rdma_chunk_ctxt wi_cc; +}; + +static struct svc_rdma_write_info * +svc_rdma_write_info_alloc(struct svcxprt_rdma *rdma, + const struct svc_rdma_chunk *chunk) +{ + struct svc_rdma_write_info *info; + + info = kmalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return info; + + info->wi_chunk = chunk; + info->wi_seg_off = 0; + info->wi_seg_no = 0; + svc_rdma_cc_init(rdma, &info->wi_cc); + info->wi_cc.cc_cqe.done = svc_rdma_write_done; + return info; +} + +static void svc_rdma_write_info_free(struct svc_rdma_write_info *info) +{ + svc_rdma_cc_release(&info->wi_cc, DMA_TO_DEVICE); + kfree(info); +} + +/** + * svc_rdma_write_done - Write chunk completion + * @cq: controlling Completion Queue + * @wc: Work Completion + * + * Pages under I/O are freed by a subsequent Send completion. + */ +static void svc_rdma_write_done(struct ib_cq *cq, struct ib_wc *wc) +{ + struct ib_cqe *cqe = wc->wr_cqe; + struct svc_rdma_chunk_ctxt *cc = + container_of(cqe, struct svc_rdma_chunk_ctxt, cc_cqe); + struct svcxprt_rdma *rdma = cc->cc_rdma; + struct svc_rdma_write_info *info = + container_of(cc, struct svc_rdma_write_info, wi_cc); + + switch (wc->status) { + case IB_WC_SUCCESS: + trace_svcrdma_wc_write(wc, &cc->cc_cid); + break; + case IB_WC_WR_FLUSH_ERR: + trace_svcrdma_wc_write_flush(wc, &cc->cc_cid); + break; + default: + trace_svcrdma_wc_write_err(wc, &cc->cc_cid); + } + + svc_rdma_wake_send_waiters(rdma, cc->cc_sqecount); + + if (unlikely(wc->status != IB_WC_SUCCESS)) + svc_xprt_deferred_close(&rdma->sc_xprt); + + svc_rdma_write_info_free(info); +} + +/* State for pulling a Read chunk. + */ +struct svc_rdma_read_info { + struct svc_rqst *ri_rqst; + struct svc_rdma_recv_ctxt *ri_readctxt; + unsigned int ri_pageno; + unsigned int ri_pageoff; + unsigned int ri_totalbytes; + + struct svc_rdma_chunk_ctxt ri_cc; +}; + +static struct svc_rdma_read_info * +svc_rdma_read_info_alloc(struct svcxprt_rdma *rdma) +{ + struct svc_rdma_read_info *info; + + info = kmalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return info; + + svc_rdma_cc_init(rdma, &info->ri_cc); + info->ri_cc.cc_cqe.done = svc_rdma_wc_read_done; + return info; +} + +static void svc_rdma_read_info_free(struct svc_rdma_read_info *info) +{ + svc_rdma_cc_release(&info->ri_cc, DMA_FROM_DEVICE); + kfree(info); +} + +/** + * svc_rdma_wc_read_done - Handle completion of an RDMA Read ctx + * @cq: controlling Completion Queue + * @wc: Work Completion + * + */ +static void svc_rdma_wc_read_done(struct ib_cq *cq, struct ib_wc *wc) +{ + struct ib_cqe *cqe = wc->wr_cqe; + struct svc_rdma_chunk_ctxt *cc = + container_of(cqe, struct svc_rdma_chunk_ctxt, cc_cqe); + struct svc_rdma_read_info *info; + + switch (wc->status) { + case IB_WC_SUCCESS: + info = container_of(cc, struct svc_rdma_read_info, ri_cc); + trace_svcrdma_wc_read(wc, &cc->cc_cid, info->ri_totalbytes, + cc->cc_posttime); + break; + case IB_WC_WR_FLUSH_ERR: + trace_svcrdma_wc_read_flush(wc, &cc->cc_cid); + break; + default: + trace_svcrdma_wc_read_err(wc, &cc->cc_cid); + } + + svc_rdma_wake_send_waiters(cc->cc_rdma, cc->cc_sqecount); + cc->cc_status = wc->status; + complete(&cc->cc_done); + return; +} + +/* This function sleeps when the transport's Send Queue is congested. + * + * Assumptions: + * - If ib_post_send() succeeds, only one completion is expected, + * even if one or more WRs are flushed. This is true when posting + * an rdma_rw_ctx or when posting a single signaled WR. + */ +static int svc_rdma_post_chunk_ctxt(struct svc_rdma_chunk_ctxt *cc) +{ + struct svcxprt_rdma *rdma = cc->cc_rdma; + struct ib_send_wr *first_wr; + const struct ib_send_wr *bad_wr; + struct list_head *tmp; + struct ib_cqe *cqe; + int ret; + + if (cc->cc_sqecount > rdma->sc_sq_depth) + return -EINVAL; + + first_wr = NULL; + cqe = &cc->cc_cqe; + list_for_each(tmp, &cc->cc_rwctxts) { + struct svc_rdma_rw_ctxt *ctxt; + + ctxt = list_entry(tmp, struct svc_rdma_rw_ctxt, rw_list); + first_wr = rdma_rw_ctx_wrs(&ctxt->rw_ctx, rdma->sc_qp, + rdma->sc_port_num, cqe, first_wr); + cqe = NULL; + } + + do { + if (atomic_sub_return(cc->cc_sqecount, + &rdma->sc_sq_avail) > 0) { + cc->cc_posttime = ktime_get(); + ret = ib_post_send(rdma->sc_qp, first_wr, &bad_wr); + if (ret) + break; + return 0; + } + + percpu_counter_inc(&svcrdma_stat_sq_starve); + trace_svcrdma_sq_full(rdma); + atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail); + wait_event(rdma->sc_send_wait, + atomic_read(&rdma->sc_sq_avail) > cc->cc_sqecount); + trace_svcrdma_sq_retry(rdma); + } while (1); + + trace_svcrdma_sq_post_err(rdma, ret); + svc_xprt_deferred_close(&rdma->sc_xprt); + + /* If even one was posted, there will be a completion. */ + if (bad_wr != first_wr) + return 0; + + atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail); + wake_up(&rdma->sc_send_wait); + return -ENOTCONN; +} + +/* Build and DMA-map an SGL that covers one kvec in an xdr_buf + */ +static void svc_rdma_vec_to_sg(struct svc_rdma_write_info *info, + unsigned int len, + struct svc_rdma_rw_ctxt *ctxt) +{ + struct scatterlist *sg = ctxt->rw_sg_table.sgl; + + sg_set_buf(&sg[0], info->wi_base, len); + info->wi_base += len; + + ctxt->rw_nents = 1; +} + +/* Build and DMA-map an SGL that covers part of an xdr_buf's pagelist. + */ +static void svc_rdma_pagelist_to_sg(struct svc_rdma_write_info *info, + unsigned int remaining, + struct svc_rdma_rw_ctxt *ctxt) +{ + unsigned int sge_no, sge_bytes, page_off, page_no; + const struct xdr_buf *xdr = info->wi_xdr; + struct scatterlist *sg; + struct page **page; + + page_off = info->wi_next_off + xdr->page_base; + page_no = page_off >> PAGE_SHIFT; + page_off = offset_in_page(page_off); + page = xdr->pages + page_no; + info->wi_next_off += remaining; + sg = ctxt->rw_sg_table.sgl; + sge_no = 0; + do { + sge_bytes = min_t(unsigned int, remaining, + PAGE_SIZE - page_off); + sg_set_page(sg, *page, sge_bytes, page_off); + + remaining -= sge_bytes; + sg = sg_next(sg); + page_off = 0; + sge_no++; + page++; + } while (remaining); + + ctxt->rw_nents = sge_no; +} + +/* Construct RDMA Write WRs to send a portion of an xdr_buf containing + * an RPC Reply. + */ +static int +svc_rdma_build_writes(struct svc_rdma_write_info *info, + void (*constructor)(struct svc_rdma_write_info *info, + unsigned int len, + struct svc_rdma_rw_ctxt *ctxt), + unsigned int remaining) +{ + struct svc_rdma_chunk_ctxt *cc = &info->wi_cc; + struct svcxprt_rdma *rdma = cc->cc_rdma; + const struct svc_rdma_segment *seg; + struct svc_rdma_rw_ctxt *ctxt; + int ret; + + do { + unsigned int write_len; + u64 offset; + + if (info->wi_seg_no >= info->wi_chunk->ch_segcount) + goto out_overflow; + + seg = &info->wi_chunk->ch_segments[info->wi_seg_no]; + write_len = min(remaining, seg->rs_length - info->wi_seg_off); + if (!write_len) + goto out_overflow; + ctxt = svc_rdma_get_rw_ctxt(rdma, + (write_len >> PAGE_SHIFT) + 2); + if (!ctxt) + return -ENOMEM; + + constructor(info, write_len, ctxt); + offset = seg->rs_offset + info->wi_seg_off; + ret = svc_rdma_rw_ctx_init(rdma, ctxt, offset, seg->rs_handle, + DMA_TO_DEVICE); + if (ret < 0) + return -EIO; + percpu_counter_inc(&svcrdma_stat_write); + + list_add(&ctxt->rw_list, &cc->cc_rwctxts); + cc->cc_sqecount += ret; + if (write_len == seg->rs_length - info->wi_seg_off) { + info->wi_seg_no++; + info->wi_seg_off = 0; + } else { + info->wi_seg_off += write_len; + } + remaining -= write_len; + } while (remaining); + + return 0; + +out_overflow: + trace_svcrdma_small_wrch_err(rdma, remaining, info->wi_seg_no, + info->wi_chunk->ch_segcount); + return -E2BIG; +} + +/** + * svc_rdma_iov_write - Construct RDMA Writes from an iov + * @info: pointer to write arguments + * @iov: kvec to write + * + * Returns: + * On success, returns zero + * %-E2BIG if the client-provided Write chunk is too small + * %-ENOMEM if a resource has been exhausted + * %-EIO if an rdma-rw error occurred + */ +static int svc_rdma_iov_write(struct svc_rdma_write_info *info, + const struct kvec *iov) +{ + info->wi_base = iov->iov_base; + return svc_rdma_build_writes(info, svc_rdma_vec_to_sg, + iov->iov_len); +} + +/** + * svc_rdma_pages_write - Construct RDMA Writes from pages + * @info: pointer to write arguments + * @xdr: xdr_buf with pages to write + * @offset: offset into the content of @xdr + * @length: number of bytes to write + * + * Returns: + * On success, returns zero + * %-E2BIG if the client-provided Write chunk is too small + * %-ENOMEM if a resource has been exhausted + * %-EIO if an rdma-rw error occurred + */ +static int svc_rdma_pages_write(struct svc_rdma_write_info *info, + const struct xdr_buf *xdr, + unsigned int offset, + unsigned long length) +{ + info->wi_xdr = xdr; + info->wi_next_off = offset - xdr->head[0].iov_len; + return svc_rdma_build_writes(info, svc_rdma_pagelist_to_sg, + length); +} + +/** + * svc_rdma_xb_write - Construct RDMA Writes to write an xdr_buf + * @xdr: xdr_buf to write + * @data: pointer to write arguments + * + * Returns: + * On success, returns zero + * %-E2BIG if the client-provided Write chunk is too small + * %-ENOMEM if a resource has been exhausted + * %-EIO if an rdma-rw error occurred + */ +static int svc_rdma_xb_write(const struct xdr_buf *xdr, void *data) +{ + struct svc_rdma_write_info *info = data; + int ret; + + if (xdr->head[0].iov_len) { + ret = svc_rdma_iov_write(info, &xdr->head[0]); + if (ret < 0) + return ret; + } + + if (xdr->page_len) { + ret = svc_rdma_pages_write(info, xdr, xdr->head[0].iov_len, + xdr->page_len); + if (ret < 0) + return ret; + } + + if (xdr->tail[0].iov_len) { + ret = svc_rdma_iov_write(info, &xdr->tail[0]); + if (ret < 0) + return ret; + } + + return xdr->len; +} + +/** + * svc_rdma_send_write_chunk - Write all segments in a Write chunk + * @rdma: controlling RDMA transport + * @chunk: Write chunk provided by the client + * @xdr: xdr_buf containing the data payload + * + * Returns a non-negative number of bytes the chunk consumed, or + * %-E2BIG if the payload was larger than the Write chunk, + * %-EINVAL if client provided too many segments, + * %-ENOMEM if rdma_rw context pool was exhausted, + * %-ENOTCONN if posting failed (connection is lost), + * %-EIO if rdma_rw initialization failed (DMA mapping, etc). + */ +int svc_rdma_send_write_chunk(struct svcxprt_rdma *rdma, + const struct svc_rdma_chunk *chunk, + const struct xdr_buf *xdr) +{ + struct svc_rdma_write_info *info; + struct svc_rdma_chunk_ctxt *cc; + int ret; + + info = svc_rdma_write_info_alloc(rdma, chunk); + if (!info) + return -ENOMEM; + cc = &info->wi_cc; + + ret = svc_rdma_xb_write(xdr, info); + if (ret != xdr->len) + goto out_err; + + trace_svcrdma_post_write_chunk(&cc->cc_cid, cc->cc_sqecount); + ret = svc_rdma_post_chunk_ctxt(cc); + if (ret < 0) + goto out_err; + return xdr->len; + +out_err: + svc_rdma_write_info_free(info); + return ret; +} + +/** + * svc_rdma_send_reply_chunk - Write all segments in the Reply chunk + * @rdma: controlling RDMA transport + * @rctxt: Write and Reply chunks from client + * @xdr: xdr_buf containing an RPC Reply + * + * Returns a non-negative number of bytes the chunk consumed, or + * %-E2BIG if the payload was larger than the Reply chunk, + * %-EINVAL if client provided too many segments, + * %-ENOMEM if rdma_rw context pool was exhausted, + * %-ENOTCONN if posting failed (connection is lost), + * %-EIO if rdma_rw initialization failed (DMA mapping, etc). + */ +int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma, + const struct svc_rdma_recv_ctxt *rctxt, + const struct xdr_buf *xdr) +{ + struct svc_rdma_write_info *info; + struct svc_rdma_chunk_ctxt *cc; + struct svc_rdma_chunk *chunk; + int ret; + + if (pcl_is_empty(&rctxt->rc_reply_pcl)) + return 0; + + chunk = pcl_first_chunk(&rctxt->rc_reply_pcl); + info = svc_rdma_write_info_alloc(rdma, chunk); + if (!info) + return -ENOMEM; + cc = &info->wi_cc; + + ret = pcl_process_nonpayloads(&rctxt->rc_write_pcl, xdr, + svc_rdma_xb_write, info); + if (ret < 0) + goto out_err; + + trace_svcrdma_post_reply_chunk(&cc->cc_cid, cc->cc_sqecount); + ret = svc_rdma_post_chunk_ctxt(cc); + if (ret < 0) + goto out_err; + + return xdr->len; + +out_err: + svc_rdma_write_info_free(info); + return ret; +} + +/** + * svc_rdma_build_read_segment - Build RDMA Read WQEs to pull one RDMA segment + * @info: context for ongoing I/O + * @segment: co-ordinates of remote memory to be read + * + * Returns: + * %0: the Read WR chain was constructed successfully + * %-EINVAL: there were not enough rq_pages to finish + * %-ENOMEM: allocating a local resources failed + * %-EIO: a DMA mapping error occurred + */ +static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info, + const struct svc_rdma_segment *segment) +{ + struct svc_rdma_recv_ctxt *head = info->ri_readctxt; + struct svc_rdma_chunk_ctxt *cc = &info->ri_cc; + struct svc_rqst *rqstp = info->ri_rqst; + unsigned int sge_no, seg_len, len; + struct svc_rdma_rw_ctxt *ctxt; + struct scatterlist *sg; + int ret; + + len = segment->rs_length; + sge_no = PAGE_ALIGN(info->ri_pageoff + len) >> PAGE_SHIFT; + ctxt = svc_rdma_get_rw_ctxt(cc->cc_rdma, sge_no); + if (!ctxt) + return -ENOMEM; + ctxt->rw_nents = sge_no; + + sg = ctxt->rw_sg_table.sgl; + for (sge_no = 0; sge_no < ctxt->rw_nents; sge_no++) { + seg_len = min_t(unsigned int, len, + PAGE_SIZE - info->ri_pageoff); + + if (!info->ri_pageoff) + head->rc_page_count++; + + sg_set_page(sg, rqstp->rq_pages[info->ri_pageno], + seg_len, info->ri_pageoff); + sg = sg_next(sg); + + info->ri_pageoff += seg_len; + if (info->ri_pageoff == PAGE_SIZE) { + info->ri_pageno++; + info->ri_pageoff = 0; + } + len -= seg_len; + + /* Safety check */ + if (len && + &rqstp->rq_pages[info->ri_pageno + 1] > rqstp->rq_page_end) + goto out_overrun; + } + + ret = svc_rdma_rw_ctx_init(cc->cc_rdma, ctxt, segment->rs_offset, + segment->rs_handle, DMA_FROM_DEVICE); + if (ret < 0) + return -EIO; + percpu_counter_inc(&svcrdma_stat_read); + + list_add(&ctxt->rw_list, &cc->cc_rwctxts); + cc->cc_sqecount += ret; + return 0; + +out_overrun: + trace_svcrdma_page_overrun_err(cc->cc_rdma, rqstp, info->ri_pageno); + return -EINVAL; +} + +/** + * svc_rdma_build_read_chunk - Build RDMA Read WQEs to pull one RDMA chunk + * @info: context for ongoing I/O + * @chunk: Read chunk to pull + * + * Return values: + * %0: the Read WR chain was constructed successfully + * %-EINVAL: there were not enough resources to finish + * %-ENOMEM: allocating a local resources failed + * %-EIO: a DMA mapping error occurred + */ +static int svc_rdma_build_read_chunk(struct svc_rdma_read_info *info, + const struct svc_rdma_chunk *chunk) +{ + const struct svc_rdma_segment *segment; + int ret; + + ret = -EINVAL; + pcl_for_each_segment(segment, chunk) { + ret = svc_rdma_build_read_segment(info, segment); + if (ret < 0) + break; + info->ri_totalbytes += segment->rs_length; + } + return ret; +} + +/** + * svc_rdma_copy_inline_range - Copy part of the inline content into pages + * @info: context for RDMA Reads + * @offset: offset into the Receive buffer of region to copy + * @remaining: length of region to copy + * + * Take a page at a time from rqstp->rq_pages and copy the inline + * content from the Receive buffer into that page. Update + * info->ri_pageno and info->ri_pageoff so that the next RDMA Read + * result will land contiguously with the copied content. + * + * Return values: + * %0: Inline content was successfully copied + * %-EINVAL: offset or length was incorrect + */ +static int svc_rdma_copy_inline_range(struct svc_rdma_read_info *info, + unsigned int offset, + unsigned int remaining) +{ + struct svc_rdma_recv_ctxt *head = info->ri_readctxt; + unsigned char *dst, *src = head->rc_recv_buf; + struct svc_rqst *rqstp = info->ri_rqst; + unsigned int page_no, numpages; + + numpages = PAGE_ALIGN(info->ri_pageoff + remaining) >> PAGE_SHIFT; + for (page_no = 0; page_no < numpages; page_no++) { + unsigned int page_len; + + page_len = min_t(unsigned int, remaining, + PAGE_SIZE - info->ri_pageoff); + + if (!info->ri_pageoff) + head->rc_page_count++; + + dst = page_address(rqstp->rq_pages[info->ri_pageno]); + memcpy(dst + info->ri_pageno, src + offset, page_len); + + info->ri_totalbytes += page_len; + info->ri_pageoff += page_len; + if (info->ri_pageoff == PAGE_SIZE) { + info->ri_pageno++; + info->ri_pageoff = 0; + } + remaining -= page_len; + offset += page_len; + } + + return -EINVAL; +} + +/** + * svc_rdma_read_multiple_chunks - Construct RDMA Reads to pull data item Read chunks + * @info: context for RDMA Reads + * + * The chunk data lands in rqstp->rq_arg as a series of contiguous pages, + * like an incoming TCP call. + * + * Return values: + * %0: RDMA Read WQEs were successfully built + * %-EINVAL: client provided too many chunks or segments, + * %-ENOMEM: rdma_rw context pool was exhausted, + * %-ENOTCONN: posting failed (connection is lost), + * %-EIO: rdma_rw initialization failed (DMA mapping, etc). + */ +static noinline int svc_rdma_read_multiple_chunks(struct svc_rdma_read_info *info) +{ + struct svc_rdma_recv_ctxt *head = info->ri_readctxt; + const struct svc_rdma_pcl *pcl = &head->rc_read_pcl; + struct xdr_buf *buf = &info->ri_rqst->rq_arg; + struct svc_rdma_chunk *chunk, *next; + unsigned int start, length; + int ret; + + start = 0; + chunk = pcl_first_chunk(pcl); + length = chunk->ch_position; + ret = svc_rdma_copy_inline_range(info, start, length); + if (ret < 0) + return ret; + + pcl_for_each_chunk(chunk, pcl) { + ret = svc_rdma_build_read_chunk(info, chunk); + if (ret < 0) + return ret; + + next = pcl_next_chunk(pcl, chunk); + if (!next) + break; + + start += length; + length = next->ch_position - info->ri_totalbytes; + ret = svc_rdma_copy_inline_range(info, start, length); + if (ret < 0) + return ret; + } + + start += length; + length = head->rc_byte_len - start; + ret = svc_rdma_copy_inline_range(info, start, length); + if (ret < 0) + return ret; + + buf->len += info->ri_totalbytes; + buf->buflen += info->ri_totalbytes; + + buf->head[0].iov_base = page_address(info->ri_rqst->rq_pages[0]); + buf->head[0].iov_len = min_t(size_t, PAGE_SIZE, info->ri_totalbytes); + buf->pages = &info->ri_rqst->rq_pages[1]; + buf->page_len = info->ri_totalbytes - buf->head[0].iov_len; + return 0; +} + +/** + * svc_rdma_read_data_item - Construct RDMA Reads to pull data item Read chunks + * @info: context for RDMA Reads + * + * The chunk data lands in the page list of rqstp->rq_arg.pages. + * + * Currently NFSD does not look at the rqstp->rq_arg.tail[0] kvec. + * Therefore, XDR round-up of the Read chunk and trailing + * inline content must both be added at the end of the pagelist. + * + * Return values: + * %0: RDMA Read WQEs were successfully built + * %-EINVAL: client provided too many chunks or segments, + * %-ENOMEM: rdma_rw context pool was exhausted, + * %-ENOTCONN: posting failed (connection is lost), + * %-EIO: rdma_rw initialization failed (DMA mapping, etc). + */ +static int svc_rdma_read_data_item(struct svc_rdma_read_info *info) +{ + struct svc_rdma_recv_ctxt *head = info->ri_readctxt; + struct xdr_buf *buf = &info->ri_rqst->rq_arg; + struct svc_rdma_chunk *chunk; + unsigned int length; + int ret; + + chunk = pcl_first_chunk(&head->rc_read_pcl); + ret = svc_rdma_build_read_chunk(info, chunk); + if (ret < 0) + goto out; + + /* Split the Receive buffer between the head and tail + * buffers at Read chunk's position. XDR roundup of the + * chunk is not included in either the pagelist or in + * the tail. + */ + buf->tail[0].iov_base = buf->head[0].iov_base + chunk->ch_position; + buf->tail[0].iov_len = buf->head[0].iov_len - chunk->ch_position; + buf->head[0].iov_len = chunk->ch_position; + + /* Read chunk may need XDR roundup (see RFC 8166, s. 3.4.5.2). + * + * If the client already rounded up the chunk length, the + * length does not change. Otherwise, the length of the page + * list is increased to include XDR round-up. + * + * Currently these chunks always start at page offset 0, + * thus the rounded-up length never crosses a page boundary. + */ + buf->pages = &info->ri_rqst->rq_pages[0]; + length = xdr_align_size(chunk->ch_length); + buf->page_len = length; + buf->len += length; + buf->buflen += length; + +out: + return ret; +} + +/** + * svc_rdma_read_chunk_range - Build RDMA Read WQEs for portion of a chunk + * @info: context for RDMA Reads + * @chunk: parsed Call chunk to pull + * @offset: offset of region to pull + * @length: length of region to pull + * + * Return values: + * %0: RDMA Read WQEs were successfully built + * %-EINVAL: there were not enough resources to finish + * %-ENOMEM: rdma_rw context pool was exhausted, + * %-ENOTCONN: posting failed (connection is lost), + * %-EIO: rdma_rw initialization failed (DMA mapping, etc). + */ +static int svc_rdma_read_chunk_range(struct svc_rdma_read_info *info, + const struct svc_rdma_chunk *chunk, + unsigned int offset, unsigned int length) +{ + const struct svc_rdma_segment *segment; + int ret; + + ret = -EINVAL; + pcl_for_each_segment(segment, chunk) { + struct svc_rdma_segment dummy; + + if (offset > segment->rs_length) { + offset -= segment->rs_length; + continue; + } + + dummy.rs_handle = segment->rs_handle; + dummy.rs_length = min_t(u32, length, segment->rs_length) - offset; + dummy.rs_offset = segment->rs_offset + offset; + + ret = svc_rdma_build_read_segment(info, &dummy); + if (ret < 0) + break; + + info->ri_totalbytes += dummy.rs_length; + length -= dummy.rs_length; + offset = 0; + } + return ret; +} + +/** + * svc_rdma_read_call_chunk - Build RDMA Read WQEs to pull a Long Message + * @info: context for RDMA Reads + * + * Return values: + * %0: RDMA Read WQEs were successfully built + * %-EINVAL: there were not enough resources to finish + * %-ENOMEM: rdma_rw context pool was exhausted, + * %-ENOTCONN: posting failed (connection is lost), + * %-EIO: rdma_rw initialization failed (DMA mapping, etc). + */ +static int svc_rdma_read_call_chunk(struct svc_rdma_read_info *info) +{ + struct svc_rdma_recv_ctxt *head = info->ri_readctxt; + const struct svc_rdma_chunk *call_chunk = + pcl_first_chunk(&head->rc_call_pcl); + const struct svc_rdma_pcl *pcl = &head->rc_read_pcl; + struct svc_rdma_chunk *chunk, *next; + unsigned int start, length; + int ret; + + if (pcl_is_empty(pcl)) + return svc_rdma_build_read_chunk(info, call_chunk); + + start = 0; + chunk = pcl_first_chunk(pcl); + length = chunk->ch_position; + ret = svc_rdma_read_chunk_range(info, call_chunk, start, length); + if (ret < 0) + return ret; + + pcl_for_each_chunk(chunk, pcl) { + ret = svc_rdma_build_read_chunk(info, chunk); + if (ret < 0) + return ret; + + next = pcl_next_chunk(pcl, chunk); + if (!next) + break; + + start += length; + length = next->ch_position - info->ri_totalbytes; + ret = svc_rdma_read_chunk_range(info, call_chunk, + start, length); + if (ret < 0) + return ret; + } + + start += length; + length = call_chunk->ch_length - start; + return svc_rdma_read_chunk_range(info, call_chunk, start, length); +} + +/** + * svc_rdma_read_special - Build RDMA Read WQEs to pull a Long Message + * @info: context for RDMA Reads + * + * The start of the data lands in the first page just after the + * Transport header, and the rest lands in rqstp->rq_arg.pages. + * + * Assumptions: + * - A PZRC is never sent in an RDMA_MSG message, though it's + * allowed by spec. + * + * Return values: + * %0: RDMA Read WQEs were successfully built + * %-EINVAL: client provided too many chunks or segments, + * %-ENOMEM: rdma_rw context pool was exhausted, + * %-ENOTCONN: posting failed (connection is lost), + * %-EIO: rdma_rw initialization failed (DMA mapping, etc). + */ +static noinline int svc_rdma_read_special(struct svc_rdma_read_info *info) +{ + struct xdr_buf *buf = &info->ri_rqst->rq_arg; + int ret; + + ret = svc_rdma_read_call_chunk(info); + if (ret < 0) + goto out; + + buf->len += info->ri_totalbytes; + buf->buflen += info->ri_totalbytes; + + buf->head[0].iov_base = page_address(info->ri_rqst->rq_pages[0]); + buf->head[0].iov_len = min_t(size_t, PAGE_SIZE, info->ri_totalbytes); + buf->pages = &info->ri_rqst->rq_pages[1]; + buf->page_len = info->ri_totalbytes - buf->head[0].iov_len; + +out: + return ret; +} + +/** + * svc_rdma_process_read_list - Pull list of Read chunks from the client + * @rdma: controlling RDMA transport + * @rqstp: set of pages to use as Read sink buffers + * @head: pages under I/O collect here + * + * The RPC/RDMA protocol assumes that the upper layer's XDR decoders + * pull each Read chunk as they decode an incoming RPC message. + * + * On Linux, however, the server needs to have a fully-constructed RPC + * message in rqstp->rq_arg when there is a positive return code from + * ->xpo_recvfrom. So the Read list is safety-checked immediately when + * it is received, then here the whole Read list is pulled all at once. + * The ingress RPC message is fully reconstructed once all associated + * RDMA Reads have completed. + * + * Return values: + * %1: all needed RDMA Reads were posted successfully, + * %-EINVAL: client provided too many chunks or segments, + * %-ENOMEM: rdma_rw context pool was exhausted, + * %-ENOTCONN: posting failed (connection is lost), + * %-EIO: rdma_rw initialization failed (DMA mapping, etc). + */ +int svc_rdma_process_read_list(struct svcxprt_rdma *rdma, + struct svc_rqst *rqstp, + struct svc_rdma_recv_ctxt *head) +{ + struct svc_rdma_read_info *info; + struct svc_rdma_chunk_ctxt *cc; + int ret; + + info = svc_rdma_read_info_alloc(rdma); + if (!info) + return -ENOMEM; + cc = &info->ri_cc; + info->ri_rqst = rqstp; + info->ri_readctxt = head; + info->ri_pageno = 0; + info->ri_pageoff = 0; + info->ri_totalbytes = 0; + + if (pcl_is_empty(&head->rc_call_pcl)) { + if (head->rc_read_pcl.cl_count == 1) + ret = svc_rdma_read_data_item(info); + else + ret = svc_rdma_read_multiple_chunks(info); + } else + ret = svc_rdma_read_special(info); + if (ret < 0) + goto out_err; + + trace_svcrdma_post_read_chunk(&cc->cc_cid, cc->cc_sqecount); + init_completion(&cc->cc_done); + ret = svc_rdma_post_chunk_ctxt(cc); + if (ret < 0) + goto out_err; + + ret = 1; + wait_for_completion(&cc->cc_done); + if (cc->cc_status != IB_WC_SUCCESS) + ret = -EIO; + + /* rq_respages starts after the last arg page */ + rqstp->rq_respages = &rqstp->rq_pages[head->rc_page_count]; + rqstp->rq_next_page = rqstp->rq_respages + 1; + + /* Ensure svc_rdma_recv_ctxt_put() does not try to release pages */ + head->rc_page_count = 0; + +out_err: + svc_rdma_read_info_free(info); + return ret; +} |